Inequality in health related to race/ethnicity, income and education continues to characterize the US population. Little is known about the way these factors interact to affect health outcomes or the role played by the physical environment and other contextual factors, which are also likely to covary with race/ethnicity. This study focuses on how numerous community characteristics interact with race/ethnicity and other key socioeconomic factors to affect physical activity, inactivity, and overweight status in American youths as they make the transition from adolescence to adulthood. We intend explore this premise using data from the 3 waves (1995, 1996, 2001-2) of the National Longitudinal Study of Adolescent Health We will link relevant contextual data with respondents' residential location in wave lI, when many will have moved to new contexts (e.g., college, employment, military service). We will develop measures of access to recreation facilities (e.g., private and public facilities, parks, recreation centers, green spaces, and shopping centers), transportation options (sidewalks, bike paths, public transportation, road network, and transportation density), proximity of road safety hazards and air pollution (correlated and other), and community safety. We will link price data (cigarettes, food, cost of living) for all periods. We develop and estimate models that relate contextual variables as well as race/ethnicity to activity, inactivity and to the likelihood of overweight in young adults. We argue that one must first consider career and residential choice decisions in order to examine how context affects physical activity, and to understand the uneven distribution of access to a wide range of environmental resources. Overweight status and physical activity preferences may affect these decisions. Therefore, our models must account for the endogeneity of career and residential choice, since failure to do so could bias our estimates of the effects of context on activity and overweight. We will also consider issues related to sample selectivity, within race heterogeneity and acculturation.